This document discusses various canal cleaning techniques, including hand instrumentation and rotary nickel-titanium techniques. It describes different types of endodontic instruments such as barbed broaches, K-files, Hedstrom files, and rotary instruments like ProTaper files, Race files, and ultrasonic/sonic instruments. It provides details on the manufacturing, uses, and modifications of various instruments used for shaping and cleaning root canals.

1. CANAL CLEANING TECHNIQUES
BDS YEAR IV
Makerere University

2. OUTLINE
 Hand Instrumentation
 Rotary Instrumentation (Nickel-titanium rotary techniques)
 Disinfection and smear layer management

3. INTRODUCTION
Endodontic treatment can be divided into three main phases:
 Proper access preparation into the pulp space
 Shaping and cleaning of the root canal
 Obturation
CLEANING-Debridement of the canal
 Removal of vital and necrotic pulp tissue,bacteria,bacterial
byproducts, dentinal debris created during instrumentation.
 Irrigation and disinfection are integral part.

4. BASIC PRINCIPLES OF CANAL INSTRUMENTATION
 There should be a straight line access to the canal orifices
 Files are always worked within a canal filled with irrigant.
 Preparation of canal should be completed while retaining its original
form and the shape
 Exploration of the orifice is always done with smaller file to gauge
the canal size and the configuration.
 Canal enlargement should be done by using instruments in the
sequential order without skipping sizes .
 After each insertion and removal of the file, its flutes should be
cleaned and inspected.

5. ENDODONTIC INSTRUMENTS FOR SHAPING AND CLEANING
Ingle and LeVine’s Standardization of Endodontic Instruments

6. CONT….
 Instruments shall be numbered from 10 to 100; the numbers to
advance by 5 units to size 60 and then by 10 units to size 100. This
has been revised to include numbers from 6 to 140.
 ƒƒEach number shall be representative of the diameter of the
instrument in hundredths of a millimeter at the tip; e.g., No. 10 is
10/100 or 0.1 mm at the tip.
 ƒƒThe working blade (flutes) shall begin at the tip, designated site
D0, and shall extend exactly 16 mm up the shaft, terminating at
designated site D16.

7. CONT….
 ƒƒThe diameter of D16 shall be 32/100 or 0.32 mm greater than that
of D0; e.g., a No. 20 reamer shall have a diameter of 0.20 mm at
D0 and a diameter of 0.20 plus 0.32 or 0.52 mm at D16.This sizing
ensures a constant increase in taper of 0.02 mm/mm for every
instrument regardless of size.
 ƒƒInstrument sizes should increase by 0.05 mm at D0,between Nos.
10 and 60, and they should increase by 0.1 mm from Nos. 60 to
150.
 ƒƒIn addition, instrument handles have been color coded for easier
recognition .

8. COMPONENTS OF AN ENDODONTIC FILE

9. CONT….
Taper: denotes the per millimeter increase in file diameter from the tip toward the
file handle, either in numericals or in percentile. A size #20 ISO file will have a tip
diameter of 0.20 mm and would have a 0.22 mm diameter 1 mm .Helps in
preparing canals of wider diameter without over enlarging the canal at working
length.

10. CONT….
Flute: It is the groove or relief on the working surface of the file which
collects the debris as the file cuts through the substrate.
Blade (cutting edge): It is the working area of the file and is the surface
with the greatest diameter that follows the flute as it rotates.
Land: In certain file designs, a surface projects axially from the central
core to the cutting edge between the flutes. This feature is incorporated to
reduce canal transportation and supports the cutting edge.
Pitch: It is the distance from one cutting edge to the next. A file with short
pitch will have more spirals than a file with a longer pitch.

11. CONT….
Rake angle: Angle formed by the leading edge with the surface to be cut.If
it forms an obtuse angle, then the rake angle is considered to be positive.
An acute angle is termed negative.
.Helix angle: It is the angle the cutting edge forms with the long axis of the
file.

12. CLASSIFICATION OF ENDODONTIC INSTRUMENTS BASED ON
METHOD OF USE
Group I: Hand-operated endodontic instruments
A. Barbed broaches and rasps
B. K-type reamers and files
C. Hedstroem files
Group II: Low-speed instruments with latch-type attachments
A. Gates-Glidden drills
B. Peeso reamers
Group III: Engine-driven instruments
A. Rotary NiTi endodontic instruments
B. Reciprocating instruments
C. Self-adjusting file (SAF)
Group IV: Ultrasonic and sonic instruments

13. ….
Barbed Broaches
MODE OF MANUFACTURE:
 Cutting sharp coronally angulated barbs into metal wires
 Available in a variety of sizes, from triple extrafine (XXXF) to
extracoarse (XC).
USES:
 Extirpation of the entire pulp.
 Removal of necrotic debris, absorbent points, cotton pledgets,
and other foreign materials from the root canal.

14. CONT….
HOW TO USE:
 The root canal is irrigated with a 5.2% solution of sodium
hypochlorite.
 The broach is introduced until one notes unforced contact with
root canal walls.
 The broach is withdrawn about 1 mm and is rotated 360° to
engage the pulp tissue; it is withdrawn again to remove the
pulp tissue.

15. K-TYPE REAMERS AND FILES
MODE OF MANUFACTURE:
 The traditional reamer - triangular blank.
file - square blank.
 Currently reamers and files are made from similar blanks, and
differ only in the number of flutes along their blade.(reamer -less
flutes, file - more flutes).
 ŠSquare blanks - instruments that resist fracture more effectively
than those made from triangular blanks and are used for smaller,
fragile instruments.
 ŠWhen instrument fracture is not a critical factor, such as in larger
instruments, triangular blanks are used since they cut
approximately 2.5 times more efficiently.

16. MODIFICATIONS:
K-flex file: Rhomboidal blanks with increased flexibility
and cutting efficiency of the instrument.
 The rhomboidal blank produces alternating high and low flutes that
are supposed to make the instrument more efficient in removal of
debris.
Flex-R file: Eliminates the possibility of ledge formation by reduction
in the cutting tip angle.
 This makes the file stay more centered within the canal and enables a
more circumferential cutting action.
Triple Flex File
 It is made up of stainless steel and are triangular in cross-section.
 It has more flutes then reamer but lesser than K-file.
 Triangular cross-section provides better flexibility and cutting
efficiency

17. HEDSTROEM FILES (H-FILES)
MODE OF MANUFACTURE:
 Milled from round stainless steel blanks to produce spiral flutes.
 Higher cutting efficiency than K-instruments, but is fragile and
fractures easily on rotational working strokes.
 Positive rake angle provides good cutting efficiency.
USE:
 Should be used in straight canals as they are not very flexible.
 File used in only one direction, retraction.

18. CONT….
MODIFICATIONS:
Safety Hedstroem: It is a file with a noncutting side in order to
prevent ledging in curved canals.
Hyflex file: It has a cross-section which presents an “S” shape
instead of the traditional single-helix teardrop cross-section of
the Hedstroem file.
Unifiles: They are machined from round stainless steel wire by
cutting two superficial grooves to produce flutes in a double-
helix design. They resemble the Hedstroem file in appearance,
less subject to fracture, but are less efficient.
S-file: It has a double-helix cross-section and is a variation of the
Unifile.

19. ROTARY ENDODONTIC INSTRUMENTS USED WITH
HANDPIECES
Low-Speed Instruments with Latch-Type Attachment
A. Gates-Glidden Drills
 Have flame shaped cutting point mounted on long thin shaft attached
to a latch type shank.
 The flame head cuts laterally. So, used with gentle, apically directed
pressure.
 Available in a set from 1 to 6 with the diameters from 0.5 to 1.5 mm.
 Gates-Glidden drills are side cutting instruments with safety tips .
 They should be used at the speed of 750 to 1500 rpm, in brushing
strokes.

20. CONT…
Uses
•Remove the lingual shoulder during access preparation
of the anterior teeth
•ŠŠEnlarge root canal orifices

21. PEESO REAMERS
• They are rotary instruments used mainly for post-space
preparations.
• They have safe ended noncutting tip.
• Their tip diameter varies from 0.7 to 1.7 mm.
• They should be used in brushing motion

22. GROUP III: ENGINE-DRIVEN INSTRUMENTS
NiTi Rotary Instruments
 In endodontics commonly used NiTi alloys are called 55
NiTinol (55% weight Ni and 45% Ti) and 60 NiTinol
(60%weight of Ni, 40% Ti).
 This superelastic alloy does not exhibit proportional strain
under stress until a specific level is attained that ultimately
causes fracture
Advantages of NiTi alloys
 Shape memory
 Superelasticity
 Good resiliency
 Corrosion resistance
 Softer than stainless steel.

23. CONT…..
Disadvantages of NiTi files
 Poor cutting efficiency
 NiTi files do not show signs of fatigue before they fracture
Generations of rotary instruments
 First generation : Profiles, Quantec
 Second generation : Profile GT
 Third generation : K3, RACE Protaper
 Fourth generation : V-taper

24. PROFILE
 The ProFile system was introduced by Dr. Ben Johnson in
1994.
 ProFile instruments have increased tapers compared with
conventional hand instruments.
 First sold as the “Series 29” hand instruments in .02 taper, but
it soon became available in .04 and .06 tapers.
 The tips of the ProFile Series 29 rotary instruments had a
constant proportion of diameter increments (29%).
 Later, a ProFile series with ISO-sized tips was developed .

25. …

26. … Cross sections of a ProFile instrument show a U-
shape design with radial lands and a parallel central
core.
 Lateral views show a 20-degree helix angle, a
constant pitch, noncutting tips and slightly negative
rake angle.
 This configuration facilitates a reaming action on
dentin rather than cutting.
 Debris is transported coronally and is effectively
removed from the root canals.

27. GREATER TAPER FILE
 The GT rotary instruments possesses a U-shaped file design
with ISO tip sizes of 20, 30 and 40 and tapers of 0.04,
0.06,0.08, 0.010 and 0.12.
 Accessory (GT) files for use as orifice openers of 0.12 taper in
ISO sizes of 35, 50, 70 and 90 are also available.
 Maximum diameter of GT file is 1.50 mm.
 Recommended rotational speed for GT file is 350 rpm.
 Negative rake angle of GT file makes it to scrape the dentin
rather than cutting it.

28. PROTAPER FILE
 Protaper means progressively taper.
 A unique feature of the ProTaper files is each instrument has
changing percentage of taper over the length of cutting blades.
 This progressively tapered design improves flexibility, cutting
efficiency and the safety of these files.
 Recommended speed is 150 to 350 rpm.
 ProTaper file has a triangular cross-section.

29. QUANTEC FILE SYSTEM
 Quantec file series are available in both cutting and
noncutting tips with standard size of 25 no. in 0.12, 0.10,0.08,
0.06, 0.05, 0.04, 0.03 and 0.02 tapers.
 0.02 tapered Quantec file are also available in size 15 to 60.
 Has a positive blade angle with two wide radial lands and
relief behind the lands .
 This unique design minimizes its contact with the canal,
thereby reducing the torque.

30. LIGHT SPEED SYSTEM
 This is so named because a “light” touch is needed as “speed” of
instrumentation is increased.
 Slender with thin parallel shaft and has noncutting tip with Gates-
Glidden in configuration.
 Recommended speed - 1000 to 2000 rpm.
 These are available in 21, 25, 31 and 50 mm length and ISO no. 20
to 140.
 Half sizes are also available . 22.5, 27.5, 32.5.
 Cutting heads of light speed system has three different geometric
shapes:
– Size 20 to 30 short noncutting tips at 75° cutting angle
– Size 32.5 longer noncutting tip at 33° cutting angle
– Size 35 to 140 longer noncutting tip with 21° cutting angle.

31. ….

32. RACE FILES (REAMERS WITH ALTERNATINCUTTING
EDGES)
 This file has two cutting edges, first alternates with a second
which has been placed at different angle
Advantages of RACE files
 Noncutting safety tip helps in:
– Perfect control of the instrument.
– Steers clear of lateral canals.
 Alternating cutting edges help in
– Reducing working time.
– Decreasing operation torque.
– Nonthreading or blocking effect
 Sharp cutting edges provide
– Better efficiency.
– Better debris evacuation.

33. REAL WORLD ENDO SEQUENCE FILE
 Recently introduced in NiTi rotary system.
 Has a blank design in such a way that alternating contact points
(ACPs) exist along the shank of the instrument. Because of
presence of ACPs, there is no need of radial lands, which
further make the instrument active shaper and thus more
effective.
 files are available in 0.04 and 0.06 taper having the precision
tip. Precision tip - noncutting tip which becomes active at
D1. This results in both safety as well as efficiency.
 Have variable pitch and helical angle which further increase its
efficiency by moving the debris out of canal and thus
decreasing the torque caused by debris accumulation.
 Working speed - 450 to 600 rpm.
 Sequence files come in package of four files each, i.e.
expeditor file, 0.06 taper files in extra small, small, medium and
large sizes.

34. ….
Wave One
system

35. WAVE ONE SYSTEM
 Is a single use, single file system to shape the root canal
completely from start to finish.
 In most cases, the technique only requires one hand file
followed by one single Wave One file to shape the canal
completely.
 The instruments are designed to work with a reverse cutting
action

36. GROUP IV: ULTRASONIC AND SONIC INSTRUMENTS
 Mainly for cleaning the root canals.
 The ultrasonic instrument consists of a piezoelectric or a
magnetostrictive unit that generates ultrasonic waves.
 The handpiece holds a K-file or a specially designed diamond
file that, when activated, produces movements of the shaft of
the file between 0.001 and 0.004 inch at a frequency of 25–30
kHz.
 This oscillating movement produces the cutting action of the
file and creates an ultrasonic wave of irrigant solution, which is
delivered along the side of the file into the root canal.
 The ultrasonic vibration produces heat that increases the
chemical effectiveness of the irrigating solution.
 It also produces two significant physical processes;

37. ….
Cavitation: This is the growth and collapse of bubbles, with a
resulting increase in the mechanical cleansing activity of the
solution.
 Because of this increase in thermal and mechanical activity of
the irrigating solution delivered into the root canal, removal of
debris and tissue from the isthmus and removal of the smear
layer are more efficient.
 The bactericidal action of the irrigating solution also increases.
 However, the root canal diameter does not permit cavitation
significantly
Acoustic streaming: This is the formation of small but intense
eddy currents or fluid movements around the oscillating
instrument.
 This improves the cleaning ability of the irrigant through
hydrodynamic stresses

38. …..
Ultrasonic unit. Sonic handpiece

39. FUNCTIONAL MOTIONS OF INSTRUMENTATION
REAMING
 Clockwise rotation of an instrument
 Used with reamers
FILING
 Push-pull motion of an instrument
 Used with file

40. COMBINATION OF REAMING AND FILLING
 File is inserted with a quarter turn clockwise and apically directed
pressure(reaming) and is subsequently withdrawn(filing).
 This technique has shown the occurrence of frequent ledge
formation and perforation.
 Modified by Schilder –giving a clockwise rotation of half
revolution followed by directing the instrument apically.
 Used with K-file and reamer.

41. WATCH WINDING
 It is back and forth oscillation of the endodontic instrument
right and left as it is advanced into the canal.
 Angle of rotation is usually 30 to 60 degrees.
 Less aggressive than quarter turn and pull motion because in
this motion the instrument tip is not forced into the apical area
with motion thereby reducing the frequency of instrument
errors.
 Efficient with K-type instruments(file and reamers)

42. WATCH WINDING AND PULL MOTION
 First, instrument is moved apically by rotating it right and left
through an arc.
 When instrument feels any resistance,it is taken out of the canal by
pull motion.
 Technique primarily used with Hedstroem files.
 NB:When used with H –files ,watch winding motion cannot cut
dentin because H-files can cut only during pull motion.

43. BALANCED FORCE TECHNIQUE
 This technique involves oscillation of instrument right and left
with different arcs in either direction.
 Instrument is first inserted into the canal by moving it
clockwise with one quarter turn.
 Then to cut dentin, file is rotated counter clockwise
simultaneously pushing apically to prevent it from backing out
of the canal.
 H-files and broaches do not possess left hand cutting
efficiency and are not used with this technique

44. CIRCUMFERENTIAL FILING
 ƒFollowing the cleaning and shaping of the root canal with a
small reamer and reaming to the root apex , the same-size file
is inserted into the root canal to the apex, laterally pressed
against one side of the canal wall and withdrawn with a pulling
motion, to file the dentinal wall.
 The file is reinserted and the procedure is repeated
circumferentially around the walls of the canal until the next-
size reamer could be used.

45. ANTICURVATURE FILING
 ƒThe furcal wall of the canals in the mesial roots of molars is
prone to perforation during coronal enlargement of the canals.
 To prevent this error, anticurvature filing is advocated where
the top of the handle of the instrument is pulled into the
curvature while the shank end of the handle is pushed away
from the inside of the curve (anticurvature).
 This motion balances the cutting flutes against the safer part of
the root canal

46. TECHNIQUES OF SHAPING AND CLEANING
1. Step-back technique
(a) Conventional step-back
(b) Passive step-back
2. Crown-down (step-down) technique and its modifications
(a) Crown-down pressureless
(b) Double flare
(c) Balanced force
3. Hybrid technique

47. STANDARDIZED PREPARATION TECHNIQUE
 One of the first techniques to be used
 Standardized reamers of increasing sizes were use sequentially to
enlarge the apical part of the canal.
 The coronal two-thirds were prepared mainly by reaming.
 It uses the same WL definition for all instruments introduced into
a root canal and therefore relies on the inherent shape of the
instruments to impart the final shape to the canal. Disadvantages
 Chances of loss of working length due to accumulation of dentin
debris.
 Canals prepared with standardized technique end up wider than
the instrument size would suggest.
 Does not take into consideration the elliptical forms and
large diameter of root canals

48. CONVENTIONAL STEP-BACK (TELESCOPIC) TECHNIQUE
 Involves preparation of the apical third initially followed by
middle and coronal third of the canal using larger instrument
sizes
 Recommended instruments; Hand instruments
 Principle motion of instrumentation; Coronal instrumentation
with reaming motion and apical instrumentation with
circumferential filing
Advantage
 Ability to prepare a proper apical stop prior to preparation of
the middle third and coronal third of the root canal
Limitations
 Extrusion of debris into the periapex
 Tendency to straighten in the canal
 Loss of working length

49. CLEANING PROCESS
 Estimate the working length radiographically.
 The size 10 K file followed by the size 15 K file is used in
a reaming motion against the walls of the root canal.
 Irrigate and recapitulate the canal between each
instrument change as we sequentially enlarge the canal at
working length to at least size 25.
 Once apical enlargement is completed, “step back” is
started with sequentially larger files completing the
middle third and coronal third canal preparation with each
file working 1 mm short of the previous small-sized
instrument

50. CROWN-DOWN TECHNIQUE(STEP-DOWN)
 Involves preparation of the coronal thirds of the canal first
followed by middle and apical third of the canal
 Recommended instruments ;Hand and rotary instruments
 Principle motion of instrumentation; Reaming motion
Advantage
 Shaping is easier
 Elimination of the bulk of the tissue, debris, and
microorganisms from coronal and middle third before apical
shaping
 Minimizes debris extrusion
 Better access and control over apical enlarging instruments
 Better penetration of irrigants
Limitations
 Gauging of the apical third is done as the last phase of the
procedure

51. CLEANING PROCESS
 Patency of the canal is first established with a size 8 or 10 K-
file
 Preparation of the coronal part-15–25 H-files to the point of
canal binding
 Flaring the coronal segment-GG drills Nos. 2 and 3
 Coronal to apical shaping with K files up to the working length
 Recapitulate and irrigate canals with appropriate irrigants in
between each change of the instrument to facilitate
debridement and cleaning of the canal

52. HYBRID TECHNIQUE
 Involves a combination of crown-down and step-back
techniques: Coronal-third instrumentation , Apical third then
middle third.
 Recommended instruments; Hand and rotary instruments
 Principle motion of instrumentation; Coronal instrumentation
with reaming motion and apical instrumentation with
circumferential filing
Advantages
 Ability to shape the canal predictably with hand
instrumentation
 Optimizes the advantages of crown-down and step-back
techniques.
Limitations
 Middle third preparation has to be done carefully in order to
prepare a continuous tapered canal preparation

53. DISINFECTION AND SMEAR LAYER MANAGEMENT
 Disinfection in endodontics is achieved through
irrigation.The objectives of irrigation are mechanical,
chemical, and biologic.
 The mechanical and chemical objectives are :
(1) flush out debris.
(2) lubricate the canal.
(3) dissolve organic and inorganic tissue.
(4) prevent the formation of a smear layer during
instrumentation or dissolve it once it has formed.
 Commonly used irrigants include;
 Sodium hypochlorite(0.5–5.2%)
 EDTA(17%)
 Chlorhexidine digluconate(2%)

54. SMEAR LAYER
 Smear layer is a surface film of a thickness of approximately
1-2 μ which remains on the root canal wall after
instrumentation.
 Absent on areas that are not instrumented.
 Contains both organic and inorganic components i.e. residual
vital or necrotic pulp tissue, dentin particles, protein
agglomerates, bacterial components, blood cells along with
retained irrigants, which blocks up the openings of the dentinal
tubules.
 The question of keeping or removing the smear layer remains
controversial

55. IN SUPPORT OF ITS REMOVAL ARE:
1. It contains bacteria, their by-products and necrotic tissue .
Bacteria may survive and multiply and can proliferate into the
dentinal tubules which may serve as a reservoir of microbial
irritants
2. It may act as a substrate for bacteria, allowing their deeper
penetration in the dentinal tubule.
3. It may limit the optimum penetration of disinfecting
agents.Bacteria may be found deep within dentinal tubules and
smear layer may block the effects of disinfectants in them.
4. It can act as a barrier between filling materials and the canal
wall and therefore compromise the formation of a satisfactory
seal.
5.It is a loosely adherent structure and a potential avenue for
leakage and bacterial contaminant passage between the root
canal filling and the dentinal walls.

56. FOR RETAINING THE SMEAR LAYER:
1.The smear layer serves as a barrier to prevent bacterial
migration into the dentinal tubules incase the canals were
inadequately disinfected, or if bacterial contamination occurred
after canal preparation.
Methods to remove the smear layer
 Current methods of smear removal include chemical,ultrasonic
and laser techniques
Chemical removal-Sodium hypochlorite and EDTA
 There is no single solution which has the ability to dissolve
organic tissues and to demineralize the smear layer, so the
sequential use of organic and inorganic solvents has been
recommended.

57. LASER REMOVAL
 Lasers can be used to vaporize tissues in the main canal,
remove the smear layer and eliminate residual tissue in the
apical portion of root canals.

58. ……
Thank you